The present invention relates to a holding device for a lens such as a photographing lens for use in a relatively low cost camera or a single lens for a recording apparatus.
Since a high performance plastic lens can now be manufactured, a lens made of a resin composed of transparent acrylic material, that is, a plastic lens, is used for a photographing lens of a relatively low cost camera, a condenser lens of a laser recording apparatus, or the like.
The plastic lens is manufactured, as widely known, by means of injection molding of resin, for which metallic molds are used. In this case, generally a plurality of metallic molds are prepared for mass production, and a plurality of cavities are made in one metallic mold when the size of plastic lens is small, and thereby it is inevitable that some dispersion is produced, for example, in a focal length depending on the difference between metallic molds or cavities used in manufacturing different lots.
Therefore, when the lens is mounted, an adjusting operation of the lens position is required, and a method by which the number of thin spacers sandwiched between mounting surfaces is increased or decreased, or a method by which the lens position is adjusted finely in the optical axis direction by rotating the lens which is contacted with an inclined surface with pressure through an elastic member, is conducted conventionally.
However, additional members such as the spacer or the elastic member are necessary for the above-mentioned methods, and further the operation which adjusts them is troublesome and inefficient, and therefore these become factors which increase the cost. Further, when lens holding is conducted by contacting the lens with the inclined surface, the adjusting operation must be conducted while confirming the focal position by means of a magnifier or the like.